Friday, June 18, 2021

Random Roll: DMG, p. 28

Page 28 of the AD&D Dungeon Masters Guide contains numerous short sections about the minutiae of combat. I'm not going to discuss them all in this post. Instead, I'm going to focus on those that I find noteworthy for one reason or another, starting with the section on helmets.

It is assumed that an appropriate type of head armoring will be added to the suit of armor in order to allow uniform protection of the wearer. Wearing of a "great helm" adds the appropriate weight and restricts vision to the front 60' only, but gives the head AC 1. If a helmet is not worn, 1 blow in 6 will strike at the AC 10 head, unless the opponent is intelligent, in which case 1 blow in 2 will be aimed at the AC 10 head (d6, 1–3 = head blow).

I've mentioned before that this is one of my favorite obscure rules in AD&D. It was certainly one I regularly sought out, because I knew it was in the DMG somewhere; I just couldn't always remember precisely where. For the most part, this rule makes sense and is probably an improvement over OD&D's silence on the subject, despite the fact that a helmet is included in the equipment list. 

Next up are magic armor and shields, which have interesting properties.

When magic armor is worn, assume that its properties allow movement at the next higher base rate and that weight is cut by 50%. There is no magical elfin chain mail.

Again, this is reasonable. I only note that Unearthed Arcana, penned by Gygax himself, includes magical elfin chain mail. 

Magic shields are no less weighty than their non-magical counterparts, but they are non-bulky with respect to encumbrance. 

I wonder why magical armor is less weighty but not magical shields. I don't object to the ruling, but I am curious as to Gygax's thinking. In any case, he continues to talk about shields and their use. Gygax begins by noting that

The shield can be used fully only to the left or front of the right handed individual. Attacks from the right flank or rear negate the benefits of a shield.

As a southpaw myself, I appreciate the acknowledgment of left handed combatants! More interesting, though, I think are his combats about large shields.

Therefore, large shields are treated as but +1 to armor class rating without a shield. Optionally, you may allow them to add +2 to this armor class with respect to small (non-war engine or giant hurled) missiles

The last point Gygax addresses is one that I've struggled with many times, namely the matter of weapon versus armor class adjustments. This is something I want to include, because it seems obvious to me that different weapons were created and wielded precisely because some were more effective in certain circumstances than in others. At the same time, the complexity likely required to address this worries me, which is why I've generally never found a system I fully embraced. AD&D includes such a system, but I've never found it very workable, for reasons Gygax discusses.

If you allow weapon type adjustments in your campaign please be certain to remember that these adjustments are for weapons versus specific types of armor, not necessarily against actual armor class.

This is something that's also stated in the Players Handbook, but I think it's important that Gygax reiterates it, lest the table there be misunderstood. That said, he also reiterates another point that I think militates against the system's ultimate utility.

In most cases, monsters not wearing armor will not have any weapon type adjustments allowed, as monster armor class in such cases pertains to the size, shape, agility, speed, and/or magical nature of the creature.

This is exactly why I was never able to adopt the weapon adjustments. If they generally don't apply to attacks against monsters, the most common opponents of characters in Dungeons & Dragons, what's the point of such a system? Worse still, I think Gygax's statement that monster armor class is reflective of size, shape, agility, speed, and so forth throws into question just what "armor class" in a broad sense means. This tension has always existed in D&D's combat system, to be sure, but I can't help but feel that, in trying to include and make sense of weapon adjustments, Gygax has opened up a can of worms that threatens to undermine the entire system. That's why, despite my keen interest in modeling differences between weapons, I nevertheless favor a simple and abstract combat system, which, while not "realistic," at least avoids being incoherent. 


  1. Did you (or anyone) regularly make use of that helmet rule? I read and remembered it as soon as I got the book, but never thought it was realistically going to show up at the table. Basically, everyone in armor (which is essentially all humanoids, for all practical purposes) requires a roll before your to-hit roll to see whether you are swinging at the head or not, and if you do, you need to use a different, extreme armor class. I could imagine a full-on hit location system like that in Runequest, but this one is a little pasted on sub-rule, and supposedly gets rolled before every attack rather than as part of the damage stage of the attack sequence. I don't think I've ever heard of someone who did this.

    1. We always used the helmet rule. Still do, for the most part (it doesn't come up because everyone buys helmets!).

      It's easy enough to throw a D6 with the D20 when making an attack roll.

    2. I did some statistical analysis of the mechanic, and versus an intelligent opponent, it comes out very close to having an AC worse by 2 points if you blow off wearing your helmet.

      Also, recall that removing your helmet comes into play when listening at doors.

  2. The use of weapon vs AC adjustments makes sense in humanoid vs humanoid combat as a reflection of the relative effectiveness of differing weapons vs different armor types. But this adjustment implies that a much more complex system for combat against non-humanoid monsters should be in place. If monsters ACs are multi-factorial composites, then shouldn’t these factors come into play when assessing to hit chances? If a monster’s low AC is primarily due to its dexterity, then shouldn’t there be a to hit adjustment based on the attacker’s dexterity

    1. It doesn't say "dexterity," it says speed and agility.

      Dexterity, as originally envisioned, appears to model hand-eye coordination. In the LBBs it provided ONLY an adjustment to missile combat. In Greyhawk (where the AC adjustment first appears), it is ONLY a bonus, not a penalty, and one only received by fighters and the (new) thief class...presumably to model their expert swordsmanship (deflecting blows and whatnot) a la Leiber's Grey Mouser character.

    2. Dexterity is defined as encompassing agility in 1E

    3. In B/X too ("speed and agility," in fact).

      But that's not what the term "dexterity" means, and I don't believe that it how it was originally envisioned when the OD&D books were written. There is evidence to the contrary.

    4. 1E evolved beyond and is not beholden to ODD

  3. On the subject of weapon versus armor type adjustments, Dan "Delta" Collins has an interesting argument about where they came from and why they're messed up:

    1. Oh interesting...

      I never used these in D&D.

      I happily use the weapon vs armor table in Traveller, but Traveller tells us how creatures fit into the table. Their weapons are included and their armor is always related to one of the given armors.

      The lack of integration with monsters is ultimately why I would not use them. If we classified monster armor such that it could show up on such a table, and we rated monster attacks against the armor types, I would be down for it.

    2. Came here to post this link. Seriously, this is a major find by Delta: the WvAC tables in 1e are completely wrong! They count AC twice, which is to say, they dictate that Plate be treated as, on average, granting 14 points of protection instead of 7, Chain as granting 10 instead of 5, etc. The only way to use them consistently with the source (ie the Chainmail man to man combat table) is to disregard THACO and simply apply the WvAC modifier to a base difficulty that disregards AC. I’ve never heard of anyone using the table this way, but perhaps someone has a story to this effect…?

  4. I had an early DM who not only used the weapon-vs-armor charts at all times, he had extensive house rules for defining monster AC as an equivalent type of armor *and* he had inferior and superior armors that granted different ACs (sometimes by 2-3 points) but still counted as the same armor type for the chart mods. To put it mildly he was a simulationist GM. Worked a lot of realistic historical details into the game, which was set in a low-fantasy pseudo-Europe.

    In hindsight it was an absurdist level of detail to throw at a table of teenage kids but at the time I didn't know better. The guy probably would have been happier running Chivalry & Sorcery, methinks.

  5. There's nothing wrong with WvAC. It's a situational combat modifier, like getting +1 or -1 for high ground (depending on who has it). Complaining about WvAC is just conventional wisdom in the classic sense - everybody seems to do it, so the socially safe thing is to join in.

    Can it be improved? Sure. I disregard shields entirely, so there's one modifier per armor type. AC Type 8 is "leather armor", not "AC Type 8". AC Type 10 is "Unarmored" - which includes people like wizards wearing rings of protection.

    Just that small tweak seems to put the rule in reach for players in my game. I make sure to describe armor when they encounter something wearing it - "these hobgoblins are wearing splint mail" - and that's usually all it takes.

    It doesn't matter to me that it only is used in sometimes, and rarely when fighting monsters. People underutilize bandits and other men as opponents in their campaign world, probably because they're stringing modules. Those people will complain that everyone takes the same weapons because (as they run the game) some weapons are clearly better than others.

  6. I use weapon vs. armor type adjustments and the helmet rule.
    I don't understand the objection "the adjustments don't apply to most monsters so I don't use them ever"; the combat system is already pretty incoherent. I apply them vs. creatures like goblins, hobgoblins, and orcs as well as drow, duergar, svirfneblin, not just humans, elves, etc. so using them isn't a rare occurrence.

  7. WvAC also (I am told) has an analogy to a real-world historical arms race.

  8. The helmet rule undermines the whole concept of hit points.


    1. If you think about it, the whole idea of hit points(as per D&D rules) undermines armor class in general
      as hp's are essentially less about how much damage you can take and more thought of as "luck" points for "avoiding the killing blow". So, any armor your wearing, is in theory, part of your hit points.

    2. I'd actually be a lot more comfortable with a game that just flat-out called its "hit points" Luck and stopped tying it to physical durability. It's just semantics and it would really go over well in D&D (where the beefy warrior types with high Con would be "luckier" than graceful rogues) but I'd sure find it easier to believe someone can be lucky enough to live through dragon breath than surviving the same through sheer grit.

    3. Much in agreement. Maybe there should be two slots for hps: one for avoiding damage, the other when you do.

  9. Back in the day, we completely missed Gygax's warning that the weapon vs armour table applied to armour type and not to the numerical armour class.

    With the result that we thought it was ridiculous and didn't use it.

    Now all these years later it makes sense to me (even if it's a bit fiddly).

  10. OD&D does address the helmet rules, just not where you would expect. In Book 2: Monsters & Treasures, under the descriptions of the Helm of Reading Magic and Language, Helm of Telepathy, and the Helm of Teleportation it discusses non-protective helms (all three qualify as such).

    The Helm of Reading Magic and Languages says: "It does not protect the same way as Magic Armor, so if it is worn in combat and hit upon its wearer should be given a 10% of striking the helm and smashing it."

    The Helm of Telepathy and Helm of Teleportation both say, "Treat as non-protective helm if worn in melee."

    Therefore, 1 in 10 attacks are to the head and a lack of helmet (or wearing a non-protective helm) means the attack only has to hit AC 9 to injure the wearer (or destroy a non-protective helm).

  11. Just now poking about for info about jousting, I see a few references to the great helm. Seems it was invented for jousting. As the “friendly” tournament jousts evolved, more efforts were made to increase safety. The knight could see through the slit and turn his head up to avoid a sharp point or splinters from entering. The crest—cool decoration atop the great helm—purely for show as one might imagine.

    Search the net for “great helm joust.”

    An example from
    “During the Middle Ages, many different helmets, almost all made of metal, were developed. Among them are the spangenhelm, the great helm, the bascinet, and the frog-mouth helm, mostly for jousting tournaments.”